I Had this same problem too once ios8.1 was installed on a 4S with my Nissan Connect system.
But it's resolved now and all I did was go to Settings > Music and then turn off Lyrics and Podcast Info, Group By Album Artist and Show All Music. Next turned off iPhone. Then plugged the iPhone back into the USB cable in my car. iPhone turns on and a message appeared on my iPhone saying the connected device was not compatible with this iphone ( which I'd never seen appear before) then unplugged USB cable and turned on the three settings above which I had turned off previously.
Plugged iPhone back into the USB cable and hey presto all now working!
I have tried afterwards unplugging iphone, rebooting, turning car off and on etc etc but it still works :-)
I Have no idea why this worked, but I hope sharing this may help others with similar issues.